4 geographically dispersed parallel sysplex, 1 gdps/pprc – IBM 990 User Manual
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zSeries 990 Technical Guide
It includes a sample migration plan, describes how to monitor this new Parallel Sysplex
technology and how to determine its cost/benefit in your environment, and gives setup
recommendations.
7.4 Geographically Dispersed Parallel Sysplex
IBM Installation Services for GDPS is a total end-to-end solution that manages availability
within a site and across multiple sites. It provides the automation to manage not only
unplanned exception conditions, but also the many planned exception conditions that are
faced as a part of normal everyday processing in any I/T environment. The GDPS solution
can be tailored to specific Business Continuance requirements, and is based on either the
synchronous Peer to Peer Remote Copy (PPRC) or the asynchronous Extended Remote
Copy (XRC).
GDPS also supports the Peer-to-Peer Virtual Tape Server (PtP VTS) form of remote copying
tape data. By extending GDPS support to data resident on tape, the GDPS solution is
designed to provide continuous availability and near transparent business continuity benefits
for both disk- and tape-resident data. Enterprises should no longer be forced to develop and
utilize processes that create duplex tapes and maintain the tape copies in alternate sites.
GDPS is application independent and is enabled by means of key IBM technologies and
architectures:
Parallel Sysplex
Tivoli® Netview for z/OS or OS/390
System Automation for z/OS or OS/390
Enterprise Storage Server™ (ESS)
Peer-to-Peer Virtual Tape Server (PtP VTS)
Optical Dense or Coarse Wavelength Division Multiplexer
PPRC (Peer-to-Peer Remote Copy) architecture
XRC (Extended Remote Copy) architecture
Virtual Tape Server Remote Copy architecture
All GDPS images are running GDPS automation based upon Tivoli Netview for z/OS or
OS/390 and System Automation for z/OS or OS/390. Each image will monitor the base or
Parallel Sysplex cluster, Coupling Facilities, and storage subsystems; and maintain GDPS
status. GDPS automation can coexist with an enterprise existing automation product.
For more detailed information on GDPS, see the white paper GDPS: The e-business
Availability Solution, GF22-5114 at:
7.4.1 GDPS/PPRC
PPRC is a hardware solution that synchronously mirrors data residing on a set of disk
volumes, called primary volumes in Site 1, to secondary disk volumes on a second system at
Site 2. Only when the application site storage subsystem receives
write complete
from the
recovery site storage subsystem is the I/O signaled as completed.
The physical topology of a GDPS/PPRC consists of a base or Parallel Sysplex cluster spread
across two sites (site 1 and site 2), with one or more z/OS and/or OS/390 systems at each
sites. The maximum distance between sites is 100 km (62 miles), using the GDPS/PPRC
Cross-site Extended Distance for Parallel Sysplex RPQ (see “GDPS/PPRC Cross-site
extended distance for Parallel Sysplex” on page 175). Without the extended distance RPQ,
the distance between sites is up to 40 km, as shown in Figure 7-8 on page 173. The multisite